I. Field of the Invention
The present invention relates to mounting assemblies that enable a night vision optical assembly to be joined to a commercial video cam recorder. More specifically, the present invention relates to a mounting assembly that joins a night vision optical assembly to a video cam recorder, without modification to the optics of the video cam recorder and alters the position of the video cam recorder's handles and display to compensate for the change in the center of gravity created by the addition of the night vision optical assembly.
II. Prior Art Statement
In the prior art record there are many night vision optical assemblies that enable a person to view a target object during night time or other low light conditions. Most such night vision assemblies are independent units having an objective lens for receiving an image and an ocular lens assembly through which a person can directly view an intensified image. Since such night vision devices are independent units, they typically have either a focusable objective lens assembly and/or a focusable ocular lens assembly, so that a person using the night vision device can adjust the device to meet his/her needs. Furthermore, it is very common for such night vision devices to provide some degree of magnification to the image being viewed.
In addition to objective lens assemblies and ocular lens assemblies, night vision devices typically include an image intensifier tube, a battery source and various electronic components used control the image produced by the night vision device. As a result, night vision devices have significant mass that may exceed 1 kilogram for some models.
In many situations, such as night time photography and night time surveillance, it is desirable to couple a night vision device to a second optical device such as a camera or a video camcorder. However, when connecting such device together, problems result due to incompatible optical designs. In many cameras and video cam recorders, the objective lens assembly is a delicate unit that is coupled to the rest of the assembly only with shallow threads. Consequently, a heavy night vision device cannot be attached to these objective lens assemblies without either damaging the assembly or creating a very fragile unit that requires the utmost care in handling. Since such delicate assemblies are impractical, the delicate objective lens assembly of a camera or video cam recorder is typically removed and the night vision device is connected directly to the housing of the camera or video cam recorder. This type of assembly, however, requires the camera or video cam recorder to rely solely upon the optics of the night vision device to properly focus the intensified image onto the film of the camera or the charged coupled device of the video cam recorder. Often the optical design of the night vision device is incompatible with the optical design of the camera objective lens that it replaces. Consequently, the image received by the film in the camera or the charged coupled device of the video cam recorder is adversely affected. This often results in a very small image being recorded or an image of poor quality being recorded.
In attempt to rectify some of the optical disadvantages of substituting a night vision device in place of the objective lens assembly of a camera or video cam recorder, the prior art has often turned to the use of relay lens assemblies that join the night vision device to the camera or video cam recorder. An example of such a prior art system includes the use of the Model F6010 pocketscope night vision device manufactured by the Electro-Optical Products Division of ITT Corp., the assignee herein. The Model F6010 pocketscope is designed to be used with a custom made relay lens assembly. The relay lens assembly therein connects the Model F6010 pocketscope to a 35 mm SLR camera body where the relay lens assembly and Model F6010 pocketscope replace the objective lens normally used with the camera. The use of a relay lens does correct some of the optical design incompatibilities, however, relay lens assembly add significantly to both the cost and the complexity of the overall assembly.
A need therefore exists in the prior art for a means to couple a night vision device to a camera or video cam recorder in a manner that does not damage the camera, does not require expensive relay lens assemblies and does not detract from the quality of the image being recorded.